https://github.com/python/cpython/commit/732faf17a618d65d264ffe775fa6db4508e3d9ff
commit: 732faf17a618d65d264ffe775fa6db4508e3d9ff
branch: main
author: Irit Katriel <[email protected]>
committer: iritkatriel <[email protected]>
date: 2024-02-15T14:20:19Z
summary:
gh-115347: avoid emitting redundant NOP for the docstring with -OO (#115494)
files:
A Misc/NEWS.d/next/Core and
Builtins/2024-02-14-23-50-43.gh-issue-115347.VkHvQC.rst
M Lib/test/test_compile.py
M Python/compile.c
diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index ebb479f2de7c63..4d8647be6a14f1 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -1,4 +1,6 @@
+import contextlib
import dis
+import io
import math
import os
import unittest
@@ -812,6 +814,30 @@ def unused_code_at_end():
'RETURN_CONST',
list(dis.get_instructions(unused_code_at_end))[-1].opname)
+ @support.cpython_only
+ def test_docstring_omitted(self):
+ # See gh-115347
+ src = textwrap.dedent("""
+ def f():
+ "docstring1"
+ def h():
+ "docstring2"
+ return 42
+
+ class C:
+ "docstring3"
+ pass
+
+ return h
+ """)
+ for opt in [-1, 0, 1, 2]:
+ with self.subTest(opt=opt):
+ code = compile(src, "<test>", "exec", optimize=opt)
+ output = io.StringIO()
+ with contextlib.redirect_stdout(output):
+ dis.dis(code)
+ self.assertNotIn('NOP' , output.getvalue())
+
def test_dont_merge_constants(self):
# Issue #25843: compile() must not merge constants which are equal
# but have a different type.
diff --git a/Misc/NEWS.d/next/Core and
Builtins/2024-02-14-23-50-43.gh-issue-115347.VkHvQC.rst b/Misc/NEWS.d/next/Core
and Builtins/2024-02-14-23-50-43.gh-issue-115347.VkHvQC.rst
new file mode 100644
index 00000000000000..16f357a944ed7a
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and
Builtins/2024-02-14-23-50-43.gh-issue-115347.VkHvQC.rst
@@ -0,0 +1,2 @@
+Fix bug where docstring was replaced by a redundant NOP when Python is run
+with ``-OO``.
diff --git a/Python/compile.c b/Python/compile.c
index 15e5cf38a37b97..f95e3cd8a79fc7 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -1692,16 +1692,13 @@ compiler_unwind_fblock_stack(struct compiler *c,
location *ploc,
static int
compiler_body(struct compiler *c, location loc, asdl_stmt_seq *stmts)
{
- int i = 0;
- stmt_ty st;
- PyObject *docstring;
/* Set current line number to the line number of first statement.
This way line number for SETUP_ANNOTATIONS will always
coincide with the line number of first "real" statement in module.
If body is empty, then lineno will be set later in
optimize_and_assemble. */
if (c->u->u_scope_type == COMPILER_SCOPE_MODULE && asdl_seq_LEN(stmts)) {
- st = (stmt_ty)asdl_seq_GET(stmts, 0);
+ stmt_ty st = (stmt_ty)asdl_seq_GET(stmts, 0);
loc = LOC(st);
}
/* Every annotated class and module should have __annotations__. */
@@ -1711,16 +1708,17 @@ compiler_body(struct compiler *c, location loc,
asdl_stmt_seq *stmts)
if (!asdl_seq_LEN(stmts)) {
return SUCCESS;
}
- /* if not -OO mode, set docstring */
- if (c->c_optimize < 2) {
- docstring = _PyAST_GetDocString(stmts);
- if (docstring) {
+ Py_ssize_t first_instr = 0;
+ PyObject *docstring = _PyAST_GetDocString(stmts);
+ if (docstring) {
+ first_instr = 1;
+ /* if not -OO mode, set docstring */
+ if (c->c_optimize < 2) {
PyObject *cleandoc = _PyCompile_CleanDoc(docstring);
if (cleandoc == NULL) {
return ERROR;
}
- i = 1;
- st = (stmt_ty)asdl_seq_GET(stmts, 0);
+ stmt_ty st = (stmt_ty)asdl_seq_GET(stmts, 0);
assert(st->kind == Expr_kind);
location loc = LOC(st->v.Expr.value);
ADDOP_LOAD_CONST(c, loc, cleandoc);
@@ -1728,7 +1726,7 @@ compiler_body(struct compiler *c, location loc,
asdl_stmt_seq *stmts)
RETURN_IF_ERROR(compiler_nameop(c, NO_LOCATION, &_Py_ID(__doc__),
Store));
}
}
- for (; i < asdl_seq_LEN(stmts); i++) {
+ for (Py_ssize_t i = first_instr; i < asdl_seq_LEN(stmts); i++) {
VISIT(c, stmt, (stmt_ty)asdl_seq_GET(stmts, i));
}
return SUCCESS;
@@ -2239,7 +2237,6 @@ static int
compiler_function_body(struct compiler *c, stmt_ty s, int is_async, Py_ssize_t
funcflags,
int firstlineno)
{
- PyObject *docstring = NULL;
arguments_ty args;
identifier name;
asdl_stmt_seq *body;
@@ -2266,28 +2263,33 @@ compiler_function_body(struct compiler *c, stmt_ty s,
int is_async, Py_ssize_t f
RETURN_IF_ERROR(
compiler_enter_scope(c, name, scope_type, (void *)s, firstlineno));
- /* if not -OO mode, add docstring */
- if (c->c_optimize < 2) {
- docstring = _PyAST_GetDocString(body);
- if (docstring) {
+ Py_ssize_t first_instr = 0;
+ PyObject *docstring = _PyAST_GetDocString(body);
+ if (docstring) {
+ first_instr = 1;
+ /* if not -OO mode, add docstring */
+ if (c->c_optimize < 2) {
docstring = _PyCompile_CleanDoc(docstring);
if (docstring == NULL) {
compiler_exit_scope(c);
return ERROR;
}
}
+ else {
+ docstring = NULL;
+ }
}
if (compiler_add_const(c->c_const_cache, c->u, docstring ? docstring :
Py_None) < 0) {
Py_XDECREF(docstring);
compiler_exit_scope(c);
return ERROR;
}
- Py_XDECREF(docstring);
+ Py_CLEAR(docstring);
c->u->u_metadata.u_argcount = asdl_seq_LEN(args->args);
c->u->u_metadata.u_posonlyargcount = asdl_seq_LEN(args->posonlyargs);
c->u->u_metadata.u_kwonlyargcount = asdl_seq_LEN(args->kwonlyargs);
- for (Py_ssize_t i = docstring ? 1 : 0; i < asdl_seq_LEN(body); i++) {
+ for (Py_ssize_t i = first_instr; i < asdl_seq_LEN(body); i++) {
VISIT_IN_SCOPE(c, stmt, (stmt_ty)asdl_seq_GET(body, i));
}
if (c->u->u_ste->ste_coroutine || c->u->u_ste->ste_generator) {
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